MANCHESTER, New Hampshire (CBS) — Investigators were back in a wooded area of Manchester to search for clues in a decades-old missing person case.

Twenty-five-year-old Denise Ann Daneault was last seen on June 8, 1980. She was a divorced mother of two living on Hayward Street. That night, she had gone out to a private social club and never returned.

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Denise Ann Daneault, 25, disappeared on June 8, 1980. (Missing Persons Database photo)

On Tuesday, the FBI and local police were in the woods behind public housing units on Kimball Street. Months ago, they were brought to the same place by an anonymous tip and searched for a few days.

Search dogs led investigators to a particular area during their November search, but they were unable to dig into the frozen ground. On Tuesday, investigators in white suits teamed up with heavy machinery digging through the woods behind the housing complex.

“I literally pray every day and ask God to find her, find out what happened to her, before I die,” her friend Marie Stevens said.

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When her close friend heard investigators were returning to the spot where a search came up empty last year, she came to the scene.

Investigators in Tyvek suits use a bulldozer to search the woods in Manchester for clues in a 1980 missing person case (WBZ-TV)

“She loved her sons more than anything. She never would have left them on purpose,” Stevens said. “She was also a really good friend, and I’ve missed that friendship all these years.”

Coincidentally, the apartment is on the same street where a suspected serial killer lived at the time. Investigators say Bob Evans, who also went by Terry Rasmussen, killed another woman with the same first name, Denise Beaudin. He died in prison.

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“Obviously we’re taking a look at it. Denise went missing in June of 1980. Terry Rasmussen left with the other Denise in November of 1981, so it’s possible he was around during that time frame as well,” said NH Senior Assistant Attorney General Jeffery Strelzin.